This publication project will involve the development of a monograph encompassing a critical review of existing validation studies concerning individual and group estimates of empirical data. A review and critique of this literature in terms of relevance to health care, scientific validity, and accessibility is vital in expanding our capabilities for meeting both local and national needs involving quality assurance, health policy development, and health care delivery. The project will encompass a reformulation of this validity problem, an extensive review and critique of available published and unpublished materials on the subject, and the preparation of a monograph (150 to 200 pages) to be submitted for publication.